(a) Field
Embodiments of the present invention relate generally to liquid crystal displays. More specifically, embodiments of the present invention relate to liquid crystal displays having improved performance and manufacturability.
(b) Description of the Related Art
As one of the most widely used flat panel displays at present, a liquid crystal display (LCD) includes two display panels on which field generating electrodes such as a pixel electrode and a common electrode are formed, and a liquid crystal layer interposed between the two display panels.
The liquid crystal display (LCD) displays an image by generating an electric field in a liquid crystal layer by applying a voltage to the field generating electrodes, determining alignment directions of liquid crystal molecules of the liquid crystal layer using the generated field, and controlling polarization of incident light.
Among the LCDs, a vertically aligned mode LCD, in which liquid crystal molecules are aligned so that their long axes are perpendicular to the upper and lower panels while no electric field is applied, has been the focus of much attention because its contrast ratio is high and a wide reference viewing angle is relatively easily implemented.
In such a vertical alignment mode LCD, a plurality of domains in which alignment directions of liquid crystals are different may be formed in one pixel to implement a wide viewing angle.
As a means of forming the plurality of domains as such, there is a method of forming cutouts such as slits and the like in the field generating electrodes. Using this method, the liquid crystals are rearranged by a fringe field generated between edges of the cutouts and the field generating electrodes facing the edges thereof, thereby forming the plurality of domains.
As examples of LCDs having these domains, there are a VA mode LCD in which upper and lower substrates both are patterned using a domain-forming means, a patternless VA mode LCD in which a micro pattern is not formed in an upper substrate but is formed only in a lower substrate, and the like. A display area is divided into a plurality of domains by the domain-forming means, and the liquid crystals of each domain are generally tilted in the same direction.
Recently, an initial alignment method in which the liquid crystals have pretilts in the absence of an electric field has been proposed to improve a response speed of the liquid crystals as well as to implement a wide viewing angle. An alignment layer having various alignment directions may be used to allow the liquid crystals to have the pretilts in various directions, or an alignment aid for allowing the liquid crystals to be pretilted in the liquid crystal layer is added and an electric field is then applied to the liquid crystal layer such that the alignment aid is hardened. The alignment aid is then hardened by heat or light such as ultraviolet rays and the like, and may allow the liquid crystals to be pretilted in a predetermined direction.
In this case, the voltage is applied to each of the electric field generating electrodes to generate the electric field in the liquid crystal layer. However, since the alignment aid requires an ultraviolet (UV) curing process or the like, use of an alignment aid requires that an additional process is added to the LCD manufacturing process. Therefore, a new process line is required and thus an additional cost is incurred. Accordingly, manufacturing cost of the LCD becomes higher, additional manufacturing equipment is needed, and the manufacturing process becomes more complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.